regmap: Skip clk_put for attached clocks when freeing context

Capability to attach an existing clk to a MMIO regmap was
introduced in 4.17rc1.

However, when using attached clk, regmap does not do the clk_get.
Therefore it should not do the clk_put when freeing the MMIO
regmap context.

There does not appear to be any users of attached clocks yet
so this would be a good time to make this change before anything
depends on the existing behaviour.

Signed-off-by: James Kelly <jamespeterkelly@gmail.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>